A genetic study of the effects of the repair-deficient mei-9a mutation in Drosophila on spontaneous and X-ray-induced paternal sex chromosome loss.
The repair-deficient mutant, mei-9a in Drosophila melanogaster was investigated regarding its effect on spontaneous and X-ray-induced chromosome loss in male postmeiotic cells. From matings of males carrying a mei-9a or an ordinary ring-X and a doubly marked Y chromosome (BSYy+) with mei-9a or ordinary females, the spontaneous frequencies of complete loss, partial loss, and inferred ring-X loss (based on shifts in sex ratio female:male) were significantly higher with mei-9a than with non-mei-9a. When males were given 3000 rad X-irradiation, frequencies of induced partial loss, inferred ring-X loss and the reduction in the number of progeny per female were significantly greater with mei-9a than with non-mei-9a. The results provide evidence that the mei-9a is a potentiator of both spontaneous and X-ray-induced chromosome lesions in sperm of the Drosophila male. Evidence is presented which implicates the presence of mei-9a in the P1 female and not the male as (at least) largely responsible for the characteristic mei-9a effects.
D000818:Animals; D004260:DNA Repair; D004307:Dose-Response Relationship, Radiation; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D008297:Male; D009154:Mutation; D010641:Phenotype; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D012730:Sex Chromosomes / Q000528:radiation effects*; D012737:Sex Factors; D014965:X-Rays; D014998:Y Chromosome / Q000528:radiation effects*